Dubbed "ancient survivors of the ocean," the Chinese horseshoe crab has endured massive geological changes across hundreds of millions of years and thrives to this day. You may be unfamiliar with this creature, yet it has saved countless human lives. Its unique blood is processed into limulus reagent, which is widely adopted for the safety detection of bacterial endotoxins in medical fields. Today, however, this ancient species is struggling for survival amid growing crises. Come with us to explore the true vitality hidden beneath its tough, shell-like armor.